Topic: 51% attack explained for beginners (Read 2342 times)
Pretty nice info about that, thanks for this information mate!
Thanks a lot for this link ! It has become a lit bit clear now ! As I have heard about 51% attack and didn't actually know what it is - this article was really helpful
It was very helpful for me too. thank you a lot!
Very helpful thank you.
Wow!!
Thanks a lot for the effort in explaining everything, I really appreciate it this will definitely shed some light on things for me.
Ofir.
Thanks a lot for the effort in explaining everything, I really appreciate it this will definitely shed some light on things for me.
Ofir.
This was taken from the Bitcoin Wiki and after extensive research on the matter.
Then either the bitcoin wiki is incorrect, or you didn't understand what you read.
Again, I'd be happy if you could enlighten me on what's wrong instead of just stating that this is useless.
If you're going to be trying to teach people, it would be a good idea to figure out how to learn first. You can't always count on others to do all your work for you.
That being said, I gave you VERY GOOD advice on how exactly to learn about the things that you are trying to teach. Most of the answers you are looking for are in the Bitcoin Whitepaper. I assume that you STILL haven't even looked at it? That doesn't give me much faith in your ability to take any initiative in educating yourself.
You seem to be far more interested in teaching your beliefs to others than in learning the truth.
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Bitcoin miners use powerful computers to verify that each person who wishes to spend Bitcoins actually has Bitcoins to spend and isn’t trying to fool the system.
No. Bitcoin miners add transactions to blocks which are then distributed to all the peers to be added to their blockchain. Every full node (even ones that aren't miners) check every transaction and every block to verify that they adhere to the rules of the protocol (such as actualy having bitcoins to spend). The blockchain is simply a decentralized way of determining a consensus of the order of the transactions.
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They do this by reviewing the Blockchain – a digital file that documents every Bitcoin transaction ever made.
No. Nodes review the blockchain before relaying a transaction to verify that the transaction is valid. Miners assemble the transactions into an acceptable block by completing a difficult (meaning time consuming) to complete but easy (fast) to verify proof-of-work. This proof-of-work is a required part of the protocol that every node on the system checks. Nodes will not accept a block into their own blockchain from a peer unless it has completed the verifiable proof-of-work.
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Miners usually groups together in mining pools so they can combine their mining power and become more efficient.
No. Pools are not more efficient. They are almost always less efficient. What pools do is to decrease volatility in mining rewards.
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The power of the miners verification process comes from it’s decentralization.
No. The power of the miners process comes from the ability of a consensus to be formed about the order of transactions.
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For example, let’s say there’s a transaction that is going through the block chain.
I assume you mean, "let's say there's a transaction that someone wants added to the blockchain."
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Each miners will review this transaction and decide if the sender actually has the bitcoin he wants to send. If the majority of miners rules the transaction is valid it will go through.
No, there is no "majority wins" rule in the bitcoin protocol. Either everybody agrees, or the blockchain forks because someone is running invalid code. Then the person that is running the invalid code is no longer participating in the bitcoin blockchain, and ALL of the remaining participants agree. Bitcoin is not a democracy, it is a consensus system.
Miners (and all other full nodes) review the transactions that they receive and discard any invalid transactions. Then they attempt to build a block with an appropriate proof-of-work. All miners and nodes accept the first block they receive. If two different blocks are broadcast at nearly the same time (perhaps two different miners solve and broadcast their block at nearly the same time), then each node and miner will accept whichever block they receive first and reject the other. The blockchain will split and the network will split with some nodes accepting one block and other nodes accepting the other. Eventually a block is solved that builds on top of one of these two chains. When nodes see the longer chain, they abandon their current shorter chain and accept the longer chain as valid.
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But what if someone could get a hold of more than 50% of the network’s mining power and manipulate the system for his own needs. Theoretically speaking, if someone manages to pull off such an attack he can double spend his money – meaning he can pay with the same Bitcoin twice or even more.
Sort of. More specifically, they could reverse transactions so that the earlier spend of the bitcoins no longer exists, and then they could send a new transaction that spends the bitcoins instead. In a true "double spend", both receivers would have spendable bitcoins. In this scenario, the bitcoins that the first recipient thought he had received will simply vanish from existence.
At least now we are getting into some of the "sense of what could happen", where you got some things sort of correct.
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The attacker will also be able to prevent transactions from being confirmed and prevent other miners from generating new Bitcoins.
This is generally correct. There are a few other things that an attacker could do that would be disruptive to the system, but you've covered some of the more well known effects here.
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But more on double spending and confirmations will be reviewed in later videos.
I suppose this is probably true as well (assuming those "later videos" are eventually created).
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For now, here’s a real live example of the 51% attack. In January of 2014 one of the mining pools got so big it neared 51% of the total mining power. This of course created some panic in the Bitcoin community but was fixed shortly after by miners who left the pool in order to balance things out.
Where's the "real live example of the 51% attack"? Where in this description did transactions get reversed, or miners get prevented from earning bitcoins, or did transactions not get confirmed? You said you were going to provide "a real live example of the 51% attack", and yet I don't see anything in there about an attack at all?
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One of the things to keep in mind is that someone with so much mining power would probably make more money using this power to mine legitimately than by actually blocking transactions or double spending.
Perhaps. That depends on how carefully they manipulate the system.
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This reduces the risk for such an attack substantially.
That depends of course on whether the attacker is trying to acquire additional bitocoins at a profitable value, or if they are simply trying to destroy the bitcoin system.
This was taken from the Bitcoin Wiki and after extensive research on the matter. Again, I'd be happy if you could enlighten me on what's wrong instead of just stating that this is useless.
what do you consider to be incorrect
Almost all of it.
and what do you think should be changed.
I think you should start by reading the Bitcoin Whitepaper written by Satoshi Nakamoto.
Once you have completed that, do some research about any concepts in the white paper that you don't understand.
Once you have completed that, ask some questions about things that you couldn't find answers to with a bit of research.
Once you have completed that, you might understand the concepts well enough to try to explain them to others.
Otherwise you are either spreading incorrect information that you've heard from others who also don't understand how bitcoin works, or you are making up ideas in your imagination and spreading them as misinformation.
I'd appreciate some more constructive feedback. In other words - what do you consider to be incorrect and what do you think should be changed.
It's not 100% technically accurate
If, by "not 100% technically accurate", what you really mean is "all the technical details are completely wrong and not based in reality at all", then yes I suppose you could say that it's not 100% technically accurate.
but it gives the sense of what could happen if someone obtains more than 50% of the network's mining capabilities.
That's probably the only thing that it comes close to getting correct. It does give a sense of some of the things that an attacker could accomplish if they happen to manage to acquire more than 50% of the combined hashing power of the entire bitcoin network.
Of course, then it goes on to say "Here's a real live example of the 51% attack", and then follows that up by giving an example of a pool NOT having more than 50% of the hashing power, AND NOT performing any sort of attack.
This is a short tutorial about the 51% attack. It's not 100% technically accurate but it gives the sense of what could happen if someone obtains more than 50% of the network's mining capabilities.
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